Thermal atomic layer deposition of silicon-containing films

ABSTRACT

Silicon oxide, silicon nitride, and silicon oxynitride films may be deposited by thermal atomic layer deposition (thermal ALD) in a single wafer plasma reactor. The single wafer plasma reactor can perform thermal ALD and plasma-enhanced atomic layer deposition (PEALD). Highly conformal films may be deposited at a high deposition rate without damaging or with minimal damage to the substrate using thermal ALD. The substrate may be heated at an elevated temperature during oxidation and/or nitridation. In some implementations, the elevated temperature is between about 500 C and about 750 C. In some implementations, hydrogen and oxygen may be flowed as reactant gases during oxidation, where the hydrogen and oxygen may react in an exothermic reaction to drive formation of oxide.

INCORPORATION BY REFERENCE

A PCT Request Form is filed concurrently with this specification as partof the present application. Each application that the presentapplication claims benefit of or priority to as identified in theconcurrently filed PCT Request Form is incorporated by reference hereinin its entirety and for all purposes.

BACKGROUND

Semiconductor device fabrication includes fabrication ofmicroprocessors, logic, and memory devices. Semiconductor devicefabrication may involve deposition of oxide and/or nitride films. Asdevice and features size continue to shrink in the semiconductorindustry, and also as 3-D device structures become more prevalent inintegrated circuit (IC) design, the capability of depositing conformalfilms will continue to gain importance. Semiconductor device fabricationmay involve deposition of nitride films. Atomic layer deposition (ALD)is a film forming technique which is well-suited to the deposition ofconformal films. ALD processes may include thermal ALD andplasma-enhanced ALD.

The background provided herein is for the purposes of generallypresenting the context of the disclosure. Work of the presently namedinventors, to the extent that it is described in this background, aswell as aspects of the description that may not otherwise qualify asprior art at the time of filing, are neither expressly nor impliedlyadmitted as prior art against the present disclosure.

SUMMARY

One aspect of the disclosure relates to a method of depositing a siliconoxide film. The method includes providing a substrate in a plasmaprocessing chamber, depositing a first silicon oxide layer on asubstrate via thermal atomic layer deposition (thermal ALD) in theplasma processing chamber, and depositing a second silicon oxide layeron the substrate via plasma-enhanced atomic layer deposition (PEALD) inthe plasma processing chamber.

In some implementations, depositing the first silicon oxide layer bythermal ALD comprises heating the substrate to an elevated temperature,exposing the substrate to a silicon-containing precursor to adsorb ontoa surface of the substrate, and posing the substrate to anoxygen-containing reactant while the substrate is heated to the elevatedtemperature to drive a reaction between the oxygen-containing reactantand the silicon-containing precursor to form the first silicon oxidelayer. In some implementations, the elevated temperature is betweenabout 500° C. and about 750° C. In some implementations, theoxygen-containing reactant includes oxygen (O₂), ozone (O₃), hydrogenperoxide (H₂O₂), water (H₂O), or combinations thereof. In someimplementations, the silicon-containing precursor includes anaminosilane. In some implementations, a chamber pressure in the plasmaprocessing chamber is equal to or greater than about 7 Torr. In someimplementations, depositing the first silicon oxide layer by thermal ALDcomprises heating the substrate to an elevated temperature, exposing thesubstrate to a silicon-containing precursor to adsorb onto a surface ofthe substrate, and flowing hydrogen (H₂) and oxygen (O₂) towards thesubstrate in the plasma processing chamber while the substrate is heatedat the elevated temperature, where the hydrogen and oxygen react withinthe plasma processing chamber, where the first silicon oxide layer isformed on the substrate. In some implementations, depositing the secondsilicon oxide layer by PEALD comprises exposing the substrate to asecond silicon-containing precursor to adsorb onto a surface of thesubstrate, and exposing the substrate to plasma generated from a secondoxygen-containing reactant, where the plasma drives a reaction betweenreactive species of the second oxygen-containing reactant and the secondsilicon-containing precursor to form the second silicon oxide layer.

Another aspect of the disclosure relates to a method of depositingsilicon oxide film. The method includes heating a substrate to anelevated temperature, exposing the substrate to a silicon-containingprecursor to adsorb onto a surface of the substrate in a plasmaprocessing chamber, and flowing hydrogen (H₂) and an oxygen-containingreactant towards the substrate in the plasma processing chamber, wherethe hydrogen and the oxygen-containing reactant react within the plasmaprocessing chamber, where a layer of a silicon oxide film is formed onthe substrate.

In some implementations, the hydrogen and the oxygen-containing reactantreact in situ with one another within the plasma processing chamber inan exothermic reaction and drive formation of the layer of the siliconoxide film. In some implementations, the elevated temperature is betweenabout 500° C. and about 650° C. In some implementations, a chamberpressure of the plasma processing chamber is equal to or greater thanabout 7 Torr. In some implementations, the oxygen-containing reactantincludes oxygen (O₂) or ozone (O₃). In some implementations, the methodfurther includes applying plasma power to the plasma processing chamberto ignite plasma generated from the hydrogen and oxygen-containingreactant in the plasma processing chamber. In some implementations,flowing the hydrogen and the oxygen-containing reactant comprisesflowing the oxygen-containing reactant continuously into the plasmaprocessing chamber, and pulsing the hydrogen at regular intervals intothe plasma processing chamber. In some implementations, (i) exposing thesubstrate to the silicon-containing precursor and (ii) flowing thehydrogen and oxygen-containing reactant are performed cyclically in athermal atomic layer deposition (thermal ALD) process. In someimplementations, (i) exposing the substrate to the silicon-containingprecursor and (ii) flowing the hydrogen and oxygen-containing reactantare performed continuously in a thermal chemical vapor deposition(thermal CVD) process. In some implementations, the method furtherincludes depositing one or more additional layers the silicon oxide filmon the substrate via PEALD in the plasma processing chamber.

Another aspect of the disclosure relates to a plasma apparatus fordepositing a silicon oxide film. The plasma apparatus includes a plasmaprocessing chamber, a substrate support in the plasma processing chamberfor supporting a substrate, where the substrate support is configured tobe heated to an elevated temperature, a showerhead fluidly coupled tothe plasma processing chamber for delivery of precursors and reactantsinto the plasma processing chamber, an RF power supply configured topower plasma in the plasma processing chamber, and a controller. Thecontroller is configured with instructions for performing the followingoperations: heat the substrate to an elevated temperature, expose thesubstrate to a silicon-containing precursor to adsorb onto a surface ofthe substrate in the plasma processing chamber, and flow hydrogen (H₂)and an oxygen-containing reactant towards the substrate in the plasmaprocessing chamber, where the hydrogen and oxygen-containing reactantreact within the plasma processing chamber, where a layer of a siliconoxide film is formed on the substrate.

In some implementations, the controller is further configured withinstructions for performing the following operation: apply plasma powerto the plasma processing chamber to ignite plasma generated from thehydrogen and oxygen-containing reactant in the plasma processingchamber. In some implementations, the controller is further configuredwith instructions for performing the following operations: deposit oneor more additional layers of the silicon oxide film on the substrate viaPEALD in the plasma processing chamber.

These and other aspects are described below with reference to thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of an example thermal atomic layerdeposition (thermal ALD) furnace reactor for depositing various films.

FIG. 2 shows a schematic diagram of an example plasma reactor configuredto perform plasma-enhanced atomic layer deposition (PEALD) fordepositing various films.

FIG. 3A shows a flow diagram of an example process for depositing asilicon oxide film using thermal ALD and PEALD according to someimplementations.

FIG. 3B shows a flow diagram of an example process for depositing asilicon oxide film using thermal ALD according to some implementations.

FIG. 4 illustrates an example timing sequence diagram showing a thermalALD cycle and a PEALD cycle for depositing a silicon oxide filmaccording to some implementations.

FIG. 5 illustrates an example timing sequence diagram showing thermalALD cycles for depositing a silicon oxide film with co-flowed hydrogenand an oxygen-containing reactant according to some implementations.

FIG. 6 illustrates an example timing sequence diagram showing thermalALD cycles for depositing a silicon oxide film with low RF plasma poweraccording to some implementations.

FIG. 7 illustrates an example timing sequence diagram showing thermalALD cycles for depositing a silicon oxide film with pulsing hydrogenflow during oxidation according to some implementations.

FIG. 8 illustrates an example timing sequence diagram showing thermalALD cycles for depositing a silicon oxide film with oxygen radicalsgenerated from a remote plasma source during oxidation according to someimplementations.

FIG. 9 illustrates an example timing sequence diagram showing a thermalALD cycle with co-flowed hydrogen and oxygen followed by a PEALD cyclewith plasma oxidation/nitridation for depositing a silicon oxide filmaccording to some implementations.

FIG. 10 illustrates an example timing sequence diagram showing thermalCVD with co-flowed silicon-containing precursor, hydrogen, andoxygen-containing reactant for depositing a silicon oxide film accordingto some implementations.

FIG. 11 is a schematic diagram of an example plasma processing apparatusfor depositing a silicon oxide film using thermal ALD according to someimplementations.

FIG. 12 is a schematic diagram of an example process tool for performingthe disclosed implementations.

FIG. 13 shows an image of silicon oxide film deposited on fin structuresby thermal ALD using several ALD cycles.

DETAILED DESCRIPTION

In the present disclosure, the terms “semiconductor wafer,” “wafer,”“substrate,” “wafer substrate,” and “partially fabricated integratedcircuit” are used interchangeably. One of ordinary skill in the artwould understand that the term “partially fabricated integrated circuit”can refer to a silicon wafer during any of many stages of integratedcircuit fabrication. A wafer or substrate used in the semiconductordevice industry typically has a diameter of 200 mm, or 300 mm, or 450mm. The following detailed description assumes the present disclosure isimplemented on a wafer. However, the present disclosure is not solimited. The work piece may be of various shapes, sizes, and materials.In addition to semiconductor wafers, other work pieces that may takeadvantage of the present disclosure include various articles such asprinted circuit boards and the like.

Introduction

Silicon-containing films have various physical, chemical, and mechanicalproperties and are often used in semiconductor fabrication processes.For example, silicon nitride, silicon oxide, or silicon oxynitride filmsmay be used as diffusion barriers, gate insulators, sidewall spacers,etch stop layers, dielectric films, and encapsulation layers. Forexample, silicon oxide films may be used as a low-k dielectric film in asemiconductor device. In various applications, silicon-containing filmsare deposited by chemical vapor deposition (CVD) or atomic layerdeposition (ALD). In various implementations, the silicon-containingfilms are deposited conformally onto features of a substrate.

ALD is a technique that deposits thin layers of material usingsequential self-limiting reactions. Typically, an ALD cycle includesoperations to deliver and adsorb at least one precursor to the substratesurface, and then react the adsorbed precursor with one or morereactants to form the partial layer of film. Purge steps are ordinarilycarried out between delivery of the precursor and delivery of the one ormore reactants.

Thermal ALD uses heat to cause a reaction between the adsorbed precursorand the one or more reactants. While thermal ALD may work well todeposit certain types of materials, thermal ALD often has a slowdeposition rate due to long reaction completion times. Thermal ALD isoften performed at very high temperatures, but many chemical precursorsor reactants may decompose (e.g., pyrolysis) at such elevatedtemperatures.

PEALD uses plasma to promote reaction between the adsorbed precursor andreactant radicals within the plasma. Reactant plasma is pulsed into adeposition chamber to react with the adsorbed precursor and formdeposited material. PEALD may have a higher deposition rate and mayoperate at lower temperatures than thermal ALD. While PEALD processesmay overcome some of the shortcomings of thermal ALD, PEALD processesmay have some limitations. For example, PEALD may cause plasma damage toa substrate (e.g., etching, oxidations), and such plasma damage mayoccur on sensitive substrate materials such as silicon, germanium,silicon-germanium, carbon, and metals like molybdenum, tungsten, copper,cobalt, ruthenium, rhodium, and iridium. Additionally, PEALD may beincompatible with certain chemical precursors.

Conventional methods for depositing films by thermal ALD areaccomplished using furnace reactors or batch reactors. Some furnacereactors can be hot wall systems, which have the advantage of moreuniform temperature distributions and reduced convection effects.

FIG. 1 shows a schematic diagram of an example thermal atomic layerdeposition furnace reactor for depositing various films. It will beunderstood that the thermal ALD furnace reactor 100 can also besubstituted as a thermal CVD reactor. The thermal ALD furnace reactor100 can include a plurality of heaters 110 surrounding a wall 102 of thethermal ALD furnace reactor 100. The plurality of heaters 110 canprovide multiple heating zones that allow for some control of the axialtemperature along the thermal ALD furnace reactor 100. In someimplementations, the temperature range of the thermal ALD furnacereactor 100 is controlled to be between about 650° C. and about 1150° C.The implementation of the thermal ALD furnace reactor 100 in FIG. 1 is ahot wall system.

The thermal ALD furnace reactor 100 can include a plurality of wafers106 stacked over one another. Each of the wafers 106 may be supported bya wafer support 104 and held by gravity. The wafer-to-wafer spacingalong the vertical direction of the thermal ALD furnace reactor 100 canbe uniform. This allows for tens or hundreds of wafers 106 to be batchprocessed in a single run through the thermal ALD furnace reactor 100.The thermal ALD furnace reactor 100 is shown holding wafers 106 in avertically-separated manner, though it will be understood that thethermal ALD furnace reactor 100 can hold wafers 106 in ahorizontally-separated manner.

Reactant gases 130 enter the thermal ALD furnace reactor 100 by flowingthrough a gas inlet 122. The reactant gases 130 can include precursorsfor adsorption followed by reactant species to react with the adsorbedprecursors. The timing and rate of flow of the reactant gases 130 can becontrolled by, e.g., valves and mass flow controllers, as known in theart. The reactant gases 130 circulate through the thermal ALD furnacereactor 100 by convection and flow towards the wafers 106 by diffusion.To deposit thin films on each of the wafers 106, the thermal ALD furnacereactor 100 can be reduced to a low pressure and heated to a desirabledeposition temperature, such as a temperature greater than about 700°C., or between about 700° C. and about 850° C., or between about 700° C.and about 800° C. The high temperature drives a chemical reactionbetween the reactant gases 130 to form thin films on each of the wafers106, where the reactant gases 130 may be delivered sequentially inpulses. The reactant gases 130 are delivered through the gas inlet 122and diffuse towards each of the wafers 106. Excess reactant gases 130may exit the thermal ALD furnace reactor 100 via gas outlet 124. Thedeposition temperature must remain high to achieve a sufficientdeposition rate for sufficient throughput.

Various oxides and nitrides, such as silicon oxide, silicon nitride,aluminum nitride, aluminum oxide, and titanium oxide, may be depositedusing a thermal ALD reactor like the thermal ALD furnace reactor 100 ofFIG. 1. However, the deposition of such oxides and nitrides in thethermal ALD reactor may require a high thermal budget. For example,processing temperatures may be greater than 700° C. for thermal ALD. Inaddition, the thermal ALD reactor may suffer from chemical depletioneffects, resulting in thickness variations across each wafer surface andthrough the thermal ALD reactor from the top of the reactor to thebottom of the reactor. Moreover, subsequent wafer processing in plasmareactors may require transfers between different tools and platforms,increasing processing time, processing steps, cost, and the likelihoodof unwanted materials or particles coming into contact with the wafers.

FIG. 2 shows a schematic diagram of an example plasma reactor configuredto perform plasma-enhanced atomic layer deposition for depositingvarious films. The plasma reactor 200 includes a plasma processingchamber 210 having a substrate support 230 configured to support asubstrate 232. A first gas 242 may be delivered into the plasmaprocessing chamber 210 through a first gas inlet 252 coupled to theplasma processing chamber 210, where the first gas 242 may includeprecursors for adsorbing onto a surface of the substrate 232. A secondgas 244 may be delivered into the plasma processing chamber 210 througha second gas inlet or showerhead 254 coupled to the plasma processingchamber 210, where the second gas 244 may include gas reactants forplasma generation. It will be understood that in some implementationsthe first gas 242 may be delivered into the plasma processing chamber210 through the showerhead 254. Unreacted gas or byproducts 246 may exitthe plasma processing chamber 210 through a gas outlet or pump 256.

The plasma reactor 200 includes a power source 240 coupled to the plasmaprocessing chamber 210 and configured to generate plasma 250 in theplasma processing chamber 210. For example, the power source 240 may becoupled to either the showerhead 254 or the substrate support 230. An RFvoltage may be applied to an electrode of the showerhead 254, where theplasma 250 may be generated between two electrodes spaced apart. Theplasma 250 may be generated at relatively low pressure. The use of theplasma 250 reduces the temperature for growth/formation of films on thesubstrate 232 due to the high reactivity of radicals in the plasma 250.

Various oxides and nitrides, such as silicon oxide, silicon nitride,aluminum nitride, aluminum oxide, and titanium oxide, may be depositedusing a plasma reactor like the plasma reactor 200 of FIG. 2. Lowdeposition temperature and high reactivity of radicals in PEALDprocesses may result in many chemical reaction schemes that aredifficult or impossible with thermal ALD processes. However, PEALDprocesses may cause substrate damage such as plasma damage or plasmaoxidation on sensitive substrates.

Thermal ALD in Plasma Processing Chamber

The present disclosure relates to deposition of oxide and/or nitridefilms on a substrate using thermal ALD in a single wafer plasma reactor.The oxide and/or nitride films may be silicon-containing films, wherethe silicon-containing films may be silicon oxide (SiO_(x)), siliconnitride (Si_(x)N_(y)), or silicon oxynitride (SiO_(x)N_(y)). While suchsilicon-containing films may ordinarily be deposited by PEALD processes,such silicon-containing films may be deposited by thermal ALD within thesame plasma reactor used for PEALD processes. In some implementations,the thermal ALD performed within the same plasma reactor as the PEALDprocesses may drive thermal oxidation/nitridation at an elevatedtemperature that is less than the high temperatures used in conventionalthermal ALD furnace reactors. For example, the elevated temperature maybe between about 500° C. and about 750° C. or between about 500° C. andabout 650° C. Thermal ALD performed within the same plasma reactor asPEALD processes may enable deposition of silicon-containing films withhigh conformality, high deposition rate, limited surface oxidation,limited bending of substrate features (e.g., pillars, fins), and uniformwet etch rate along the depth of the structure, among other advantages.In other words, highly conformal films may be deposited by thermal ALDin a plasma processing chamber with little to no damage/oxidation to thesubstrate.

In some implementations of the present disclosure, thermal ALD ofsilicon-containing films in a plasma processing chamber may be achievedusing a silicon-containing precursor and multiple gas reactants thatreact with one another in situ. For example, thermal ALD of a siliconoxide film in a plasma processing chamber may be achieved using asilicon-containing precursor and hydrogen (H₂) and oxygen (O₂) thatreact in situ over a substrate to cause an exothermic reaction. Theexothermic reaction may provide energy to drive oxide formation forimproved deposition rate. In some implementations of the presentdisclosure, low RF power may be applied to the plasma processing chamberto ignite plasma while flowing hydrogen and oxygen during thermal ALD.In some implementations of the present disclosure, silicon-containingfilms may be deposited in a plasma processing chamber using thermal CVDinstead of thermal ALD. In some implementations of the presentdisclosure, silicon-containing films may be deposited in a plasmaprocessing chamber using thermal ALD followed by PEALD. In someimplementations of the present disclosure, silicon-containing films maybe deposited in a plasma processing chamber using PEALD followed bythermal ALD.

Deposition of silicon-containing films by thermal ALD in a plasmaprocessing chamber reduces damage that may otherwise be caused bydeposition of silicon-containing films by PEALD. This can be due in partto the low presence of radicals and ionic species in thermal ALD.Moreover, thermal ALD in the plasma processing chamber of the presentdisclosure reduces damage on substrates that may otherwise be caused bydeposition of silicon-containing films using conventional thermal ALDreactors operating at high thermal budgets. The silicon-containing filmsdeposited by thermal ALD in the plasma processing chamber of the presentdisclosure may be deposited at a comparable deposition rate as PEALD andmay provide as high quality film as films deposited by PEALD.

Though the present disclosure is largely described with reference tothermal ALD in the present disclosure, it will be understood that“thermal ALD” in the present disclosure can refer to reaction mechanismsfor thermal ALD reactions occurring cyclically and reaction mechanismsfor thermal CVD reactions occurring continuously. In addition, it willbe understood that though the present disclosure is largely describedwith reference to deposition of silicon oxide films, the presentdisclosure can encompass deposition of any oxide or nitride films usingthermal ALD.

FIG. 3A shows a flow diagram of an example process for depositing asilicon oxide film using thermal ALD and PEALD according to someimplementations. As used herein, the term “silicon oxide film” may referto undoped silicon oxide (e.g., SiO_(x)) films as well as doped siliconoxide (e.g., SiO_(x)N_(y)) films. The operations in a process 300 a ofFIG. 3A may be performed in different orders and/or with different,fewer, or additional operations. The operations in the process 300 a maybe performed by a plasma processing apparatus shown in FIG. 11 and/orthe process tool shown in FIG. 12. In some implementations, theoperations of the process 300 a may be implemented, at least in part,according to software stored in one or more non-transitory computerreadable media. FIGS. 3A and 4 may be described together below.

At block 310 of the process 300 a, a substrate is provided in a plasmaprocessing chamber. The plasma processing chamber may be a single waferplasma reactor configured to perform thermal ALD processes, PEALDprocesses, or combinations thereof. The substrate may be a siliconsubstrate, such as a 200-mm, 300-mm, or 450-mm substrate, includingsubstrates having one or more layers of material, such as dielectric,conducting, or semiconducting material. In some implementations, thesubstrate on which silicon oxide films are deposited may include amaterial that is sensitive to plasma damage/oxidation by PEALD. Forexample, the material may include but is not limited to silicon (Si),germanium (Ge), silicon-germanium (Si—Ge), carbon (C), and metals, whereexample metals include molybdenum (Mo), tungsten (W), copper (Cu),cobalt (Co), ruthenium (Ru), rhodium (Rh), and iridium (Ir). Thesubstrate on which the silicon oxide films are deposited may include oneor more features, which may refer to non-planar structures of asubstrate. For example, the one or more features may include verticalstructures such as fins or pillars. In some implementations, the one ormore features may include an under-layer such as a barrier layer, linerlayer, or adhesion layer.

At block 320 of the process 300 a, a first silicon oxide layer isdeposited via thermal ALD in the plasma processing chamber. Any suitablenumber of thermal ALD cycles may be performed at block 320 prior toperforming PEALD. Each thermal ALD cycle may be broken down into aseries of phases, including a dose phase, a first purge phase, a thermaloxidation phase, and a second purge phase. It will be understood thatone or both of the first purge phase and the second purge phase may beoptionally performed in each thermal ALD cycle. Depositing a thin filmvia thermal ALD includes: heating the substrate to an elevatedtemperature, exposing the substrate to a precursor to adsorb onto asurface of the substrate, and exposing the substrate to one or more gasreactants to drive a surface reaction between the one or more gasreactants and the precursor, thereby forming the thin film via thermalALD. Specifically, depositing the first silicon oxide layer via thermalALD includes: heating the substrate to an elevated temperature, exposingthe substrate to a silicon-containing precursor to adsorb onto a surfaceof the substrate, and exposing the substrate to an oxygen-containingreactant to drive a reaction between the oxygen-containing reactant andthe silicon-containing precursor, thereby forming the first siliconoxide layer via thermal ALD.

FIG. 4 illustrates an example timing sequence diagram showing a thermalALD cycle and a PEALD cycle for depositing a silicon oxide filmaccording to some implementations. FIG. 4 shows phases in a thermal ALDcycle 410A followed by phases in a PEALD cycle 410B. However, it will beunderstood that phases in the PEALD cycle 410B may be followed by phasesin the thermal ALD cycle 410A. FIG. 4 shows various process parameters,such as carrier gas or purge gas flow, plasma, silicon-containingprecursor flow, and oxygen-containing reactant flow. The lines indicatewhen the flow is turned on/off, or when plasma is turned on/off. Asshown in FIG. 4, during the thermal ALD cycle 410A, the substrate isexposed to a silicon-containing precursor during a dose phase 457A. Insome implementations, the silicon-containing precursor includes asilane, such as an aminosilane. An aminosilane includes at least onenitrogen atom bonded to a silicon atom, but may also contain hydrogens,oxygens, halogens and carbons. Examples of aminosilanes may includebis(tert-butylamino)silane (BTBAS),N-(diethylaminosilyl)-N-ethylethanamine (SAM-24),tris(dimethylamino)silane (3DMAS), and tetrakis(dimethylamino)silane(4DMAS). During the dose phase 457A, plasma is turned off,oxygen-containing reactant flow is turned off, and a carrier gas may beflowed towards the substrate. However, it will be understood that thesubstrate may be heated to an elevated temperature during the dose phase457A. In some implementations, the substrate may be exposed to thesilicon-containing precursor during the dose phase 457A for a durationbetween about 0.1 seconds and about 60 seconds, between about 0.2seconds and about 6 seconds, or between about 0.3 seconds and about 2seconds, such as about 0.75 seconds, depending on the flow rate andsubstrate surface area. In some implementations, the silicon-containingprecursor adsorbs onto the surface of the substrate in a self-limitingmanner such that once active sites are occupied by thesilicon-containing precursor, little or no additional silicon-containingprecursor will be adsorbed on the surface of the substrate. When thesilicon-containing precursor adsorbs onto active sites of the surface ofthe substrate, a thin layer of the silicon-containing precursor forms onthe surface. Unlike a CVD or CVD-like process, the silicon-containingprecursor does not decompose to form a silicon layer.

In some implementations, the plasma processing chamber may be purgedbetween operations of exposing the substrate to the silicon-containingprecursor and exposing the substrate to the oxygen-containing reactant.In addition, the plasma processing chamber may be purged after exposingthe substrate to the oxygen-containing reactant. Purging may involve asweep gas, which may be a carrier gas used in other operations/phases ora different gas. Purging may remove excess species in the vapor phasethat did not adsorb or react on the surface of the substrate. As shownin FIG. 4, the plasma processing chamber undergoes purging during purgephases 459A and 463A. Silicon-containing precursor flow is turned off,plasma is turned off, and oxygen-containing reactant flow is turned off.However, the carrier gas may continue to flow towards the substrate. Insome implementations, the purge phases 459A and 463A may each includeone or more evacuation sub-phases for evacuating the plasma processingchamber. Alternatively, it will be appreciated that each of the purgephases 459A and 463A may be omitted in some implementations. Each purgephase 459A and 463A may have a suitable duration, such as between about0 seconds and about 60 seconds or between about 0.01 seconds and about 6seconds.

As shown in FIG. 4, during the thermal ALD cycle 410A, the substrate maybe exposed to the oxygen-containing reactant and the elevatedtemperature during a thermal oxidation phase 461A. Process conditionsduring the thermal oxidation phase 461A may be tuned to promotedeposition of the first silicon oxide layer by thermal ALD at anappreciable or adequate deposition rate. For example, the depositionrate of the first silicon oxide layer by thermal ALD can be equal to orgreater than about 0.2 Å/cycle, equal to or greater than about 0.3Å/cycle, equal to or greater than about 0.5 Å/cycle, or equal to orgreater than about 0.75 Å/cycle. This may be an appreciable depositionrate when the first silicon oxide layer is used to protect a surfaceagainst oxidation/damage.

In some implementations, the oxygen-containing reactant can include anoxidant gas such as oxygen (O₂), ozone (O₃), hydrogen peroxide (H₂O₂),water (H₂O), or combinations thereof. In some implementations, exposingthe substrate to the oxygen-containing reactant includes flowinghydrogen and oxygen to the substrate to react in situ within the plasmaprocessing chamber to cause an exothermic reaction. In someimplementations, it is believed that water may be formed in situ by areaction between the hydrogen and oxygen. Water vapor is not flowed intothe plasma processing chamber as a starting reactant, but may or may notbe formed in situ within the plasma processing chamber. As used herein,flowing “hydrogen” refers to flowing molecular hydrogen and flowing“oxygen” refers to flowing molecular oxygen. The hydrogen and oxygen maybe flowed towards the substrate in the plasma processing chambersimultaneously. The exothermic reaction involving hydrogen and oxygenmay release energy for driving a surface reaction with the adsorbedsilicon-containing precursor to form the first silicon oxide layer. Aflow rate of hydrogen during the thermal oxidation phase 461A may bebetween about 0 slm and about 20 slm, between about 1 slm and about 10slm, between about 2 slm and about 6 slm, greater than about 3 slm, suchas about 4 slm. A flow rate of oxygen during the thermal oxidation phase461A may be between about 0.5 slm and about 20 slm, between about 1 slmand about 10 slm, or between about 2 slm and about 8 slm, such as about5 slm. A flow rate ratio between hydrogen and oxygen may be equal to orless than about 1.2:1, such as between about 0.5:1 and about 1.2:1.

The substrate may be exposed to the oxygen-containing reactant andexposed to an elevated temperature for a suitable duration during thethermal oxidation phase 461A. Ordinarily, thermal oxidation in furnaceor batch reactors in thermal ALD/CVD chambers may last at least 10seconds to obtain an appreciable deposition rate, particularly forsilicon oxide films. However, the duration of thermal oxidation in theplasma processing chamber of the present disclosure may be less thanabout 10 seconds. In some implementations, the duration of thermaloxidation in the thermal oxidation phase 361A may be between about 0.1seconds and about 6 seconds, between about 0.2 seconds and about 4seconds, or between about 0.5 seconds and about 3 seconds.

The substrate may be exposed to an elevated temperature during thethermal oxidation phase 461A and/or prior to the thermal oxidation phase461A. The substrate may be operating at the elevated temperaturesimultaneously with exposing the substrate to the oxygen-containingreactant. In some implementations, the elevated temperature may bebetween about 500° C. and about 750° C., between about 500° C. and about700° C., between about 500° C. and about 650° C., or between about 550°C. and about 650° C. Ordinarily, temperatures in furnace or batchreactors in thermal ALD/CVD chambers may be greater than 700° C. indriving surface reactions for deposition of silicon oxide films.However, temperatures may be equal to or less than about 700° C. indriving surface reactions for deposition of silicon oxide films bythermal ALD in a plasma processing chamber of the present disclosure.Furthermore, many conventional plasma processing chambers for PEALD donot operate at temperatures equal to or greater than about 400° C.Deposition by thermal ALD in the plasma processing chamber at theelevated temperature may be equal to or greater than about 0.2 Å/cycle.

The substrate may be exposed to increased chamber pressure during thethermal oxidation phase 461A. Increased chamber pressure may increasedeposition rate and drive the surface reaction between thesilicon-containing precursor and the oxygen-containing reactant. In someimplementations, the chamber pressure of the plasma processing chambermay be equal to or greater than about 7 Torr, equal to or greater thanabout 10 Torr, equal to or greater than about 12 Torr, or between about10 Torr and about 20 Torr. Ordinarily, a pressure in a furnace or batchreactor in thermal ALD/CVD chambers may be less than about 5 Torr.However, chamber pressure may be equal to or greater than about 5 Torrfor deposition by thermal ALD in the plasma processing chamber of thepresent disclosure. In addition, some conventional plasma processingchambers for PEALD do not typically operate at pressures equal to orgreater than 5 Torr.

The process conditions to achieve an appreciable deposition rate may bedifferent during the thermal oxidation phase 461A depending on theselected gas reactants. In some implementations, where the gas reactantconsists of oxygen, a deposition rate greater than about 0.2 Å/cycle maybe achieved at temperatures between about 550° C. and about 700° C. andchamber pressures equal to or greater than about 12 Torr. Suchimplementations may be referred to as an oxygen-only flow. In someimplementations, where the gas reactants consist of hydrogen and oxygen,a deposition rate equal to or greater than about 0.7 Å/cycle may beachieved at temperatures between about 500° C. and about 700° C. andchamber pressures equal to or greater than about 7 Torr. Suchimplementations may be referred to as a co-flow of hydrogen and oxygen(H₂/O₂). The co-flow of hydrogen and oxygen may enable higher depositionrates even at lower temperatures and pressures in the plasma processingchamber. Specifically, thermal oxidation may occur at a faster rateusing the co-flow of hydrogen and oxygen compared to an oxygen-onlyflow.

A plurality of thermal ALD cycles 410A may be performed to form thefirst silicon oxide layer on the substrate. In some implementations, thefirst silicon oxide layer deposited by thermal ALD may serve as a linerlayer prior to deposition by PEALD. The liner layer may protectunderlying layers from substrate damage and/or provide a high qualityliner in high aspect ratio structures. In some implementations, thefirst silicon oxide layer may be relatively thin and be between about 1Å and about 100 Å, such as between about 10 Å and about 100 Å. For suchthicknesses involving an oxygen-only flow, the number of thermal ALDcycles may be between about between about 5 cycles and about 50 cycles,between about 5 cycles and about 20 cycles, or between about 5 cyclesand about 10 cycles.

The first silicon oxide layer deposited by the plurality of thermal ALDcycles 410A may cause little to no damage to the substrate and little tono oxidation to the substrate. For example, an amount of siliconsubstrate oxidation may be between about 1 Å and about 3 Å when usingoxygen-only flow of thermal ALD process, whereas a typical PEALD processresults in silicon substrate oxidation between about 15 Å and about 35Å. Where the first silicon oxide layer is deposited on verticalstructures of the substrate, little to no bending occur on the verticalstructures. The wet etch rate of the first silicon oxide layer along thedepth of the vertical structures is uniform. Furthermore, where thesubstrate includes one or more features, a step coverage of the firstsilicon oxide layer is highly conformal. For example, the step coverageof the first silicon oxide layer may be equal to or greater than about85%, equal to or greater than about 90%, or equal to or greater thanabout 95%. FIG. 13 shows an image of silicon oxide film deposited on finstructures at 650° C. using thermal ALD, where the deposited siliconoxide film exhibits high conformality and limited bending of the finstructures.

At block 330 of the process 300, a second silicon oxide layer isdeposited on the substrate via PEALD in the plasma processing chamber.The thermal ALD operation at block 320 and the PEALD operation at block330 are performed in the same plasma processing chamber. Any suitablenumber of PEALD cycles may be performed at block 330 after performingthermal ALD. Each PEALD cycle may be broken down into a series ofphases, including a dose phase, a first purge phase, a plasma exposurephase, and a second purge phase. It will be understood that one or bothof the first purge phase and the second purge phase may be optionallyperformed in each PEALD cycle. Depositing a thin film via PEALDincludes: exposing the substrate to a precursor to adsorb onto a surfaceof the substrate, and exposing the substrate to plasma generated fromone or more gas reactants, where the plasma drives a reaction betweenreactive species of the one or more gas reactants and the precursor,thereby forming the thin film via PEALD. Specifically, depositing thesecond silicon oxide layer by PEALD includes: exposing the substrate toa silicon-containing precursor to adsorb onto the surface of thesubstrate, and exposing the substrate to plasma generated from anoxygen-containing reactant, where the plasma drives a reaction betweenreactive species of the oxygen-containing reactant and thesilicon-containing precursor, thereby forming the second silicon oxidelayer via PEALD. The silicon-containing precursor in the PEALD cyclesmay or may not be the same as the silicon-containing precursor in thethermal ALD cycles. In addition, the oxygen-containing reactant in thePEALD cycles may or may not be the same as the oxygen-containingreactant in the thermal ALD cycles. For example, the oxygen-containingreactant may include oxygen, ozone, or combinations thereof.

As shown in FIG. 4, during the PEALD cycle 410B, the substrate isexposed to a silicon-containing precursor during a dose phase 457B. Insome implementations, the silicon-containing precursor includes asilane, such as an aminosilane. During the dose phase 457B, plasma isturned off, oxygen-containing reactant flow is turned off, and a carriergas may be flowed towards the substrate. In some implementations, thesilicon-containing precursor adsorbs onto the surface of the substratein a self-limiting manner such that once active sites are occupied bythe silicon-containing precursor, little or no additionalsilicon-containing precursor will be adsorbed on the surface of thesubstrate.

In some implementations, the plasma processing chamber may be purgedbetween operations of exposing the substrate to the silicon-containingprecursor and exposing the substrate to an oxygen-containing reactant.In addition, the plasma processing chamber may be purged after exposingthe substrate to the oxygen-containing reactant. Purging may involve asweep gas, which may be a carrier gas used in other operations/phases ora different gas. Purging may remove excess species in the vapor phasethat did not adsorb or react onto the surface of the substrate. As shownin FIG. 4, the plasma processing chamber undergoes purging during purgephases 459B and 463B. Silicon-containing precursor flow is turned off,plasma is turned off, and oxygen-containing reactant flow is turned off.However, the carrier gas may continue to flow towards the substrate. Insome implementations, the purge phases 459B and 463B may each includeone or more evacuation sub-phases for evacuating the plasma processingchamber. Alternatively, it will be appreciated that each of the purgephases 459B and 463B may be omitted in some implementations.

As shown in FIG. 4, during the PEALD cycle 410B, the substrate may beexposed to the plasma generated from the oxygen-containing reactantduring a plasma exposure phase 461B. An oxygen plasma may be ignitedduring the plasma exposure phase 461B. The plasma may include ions,radicals, charged neutrals, and other reactive species generated fromthe oxygen-containing reactant. The reactive species from theoxygen-containing reactant may react with the adsorbedsilicon-containing precursor to form the second silicon oxide layer overthe first silicon oxide layer. The plasma may be generated in situ orremotely. Flow of the silicon-containing precursor is turned off whileflow of the oxygen-containing reactant is turned on during the plasmaexposure phase 461B.

Process conditions in the plasma processing chamber may vary for theoxygen plasma during the plasma exposure phase 461B. In someimplementations, the substrate temperature may be maintained betweenabout 0° C. and about 750° C. or between about 20° and about 200° C. Insome implementations, the chamber pressure in the plasma processingchamber may be relatively low and between about 10 mTorr and about 200mTorr, or may be relatively high and between about 1 Torr and about 7Torr. An RF field is applied to the plasma processing chamber togenerate ions and radicals of the oxygen-containing reactant. In variousimplementations, the RF frequency used to generate the plasma may be atleast about 13.56 MHz, at least about 27 MHz, at least about 40 MHz, orat least about 60 MHz, though other frequencies may also be used. Insome implementations, the RF power may be a few hundred Watts, forexample about 500 W or less, about 400 W or less, or about 300 W orless, though it will be understood that other RF powers may be applieddepending on substrate area. In some implementations, the duration ofthe plasma exposure phase 461B may be between about 0.1 seconds andabout 120 seconds or between about 1 second and about 60 seconds.

A plurality of PEALD cycles 410B may be performed to form the secondsilicon oxide layer on the first silicon oxide layer. The first siliconoxide layer deposited by thermal ALD cycles 410A may provide a linerlayer of silicon oxide film to protect underlying layers. In someimplementations, the liner layer may be relatively thin and betweenabout 10 Å and about 100 Å thick. In some implementations, the linerlayer may serve as a protective liner on soft layers to eliminate orotherwise reduce substrate damage. In some implementations, the linerlayer may serve as a high quality liner on high aspect ratio structures.Such high aspect ratio structures may include fins and pillars. The highaspect ratio structures may be prone to bending/damage when exposed toonly PEALD operations. However, having the first silicon oxide layerdeposited by thermal ALD prior to the second silicon oxide layerprovides high conformality, high deposition rate, limited surfaceoxidation, limited bending of substrate features (e.g., pillars, fins),and uniform wet etch rate on sidewalls. The second silicon oxide layerdeposited by PEALD cycles 410B may follow as bulk deposition of siliconoxide film on the liner layer. Accordingly, in various implementations,nucleation of silicon oxide film may be performed by thermal ALD andbulk deposition may be performed by PEALD in the same plasma processingchamber.

In some implementations, the process 300 a further includes exposing thesubstrate to plasma generated from a nitrogen-containing reactant in theplasma processing chamber, where the plasma drives a reaction betweenreactive species of the nitrogen-containing reactant and at least thesecond silicon oxide layer, thereby converting at least the secondsilicon oxide layer to a silicon oxynitride layer. In someimplementations, the nitrogen-containing reactant may include nitrogen(N₂), ammonia (NH₃), or combinations thereof. A nitrogen plasma maycause nitridation of one or both of the first and second silicon oxidelayer to form the silicon oxynitride layer.

In addition or in the alternative to the aforementioned nitridation ofsilicon oxide, the process 300 a may include depositing a siliconnitride layer on the first and second silicon oxide layer by thermal ALDor PEALD in the plasma processing chamber. Thus, the combination of thefirst silicon oxide layer, the second silicon oxide layer, and thesilicon nitride layer collectively form a silicon oxynitride film. Invarious implementations, silicon oxide and silicon nitride layers may bedeposited in alternating fashion to form nanolaminates of siliconoxide/silicon nitride. In some implementations, the process 300 afurther includes annealing the substrate to form the silicon oxynitridefilm from the first silicon oxide layer, the second silicon oxide layer,and the silicon nitride layer.

FIG. 3B shows a flow diagram of an example process for depositing asilicon oxide film using thermal ALD according to some implementations.The operations in a process 300 b of FIG. 3B may be performed indifferent orders and/or with different, fewer, or additional operations.The operations in the process 300 b may be performed by a plasmaprocessing apparatus shown in FIG. 11 and/or the process tool shown inFIG. 12. In some implementations, the operations of the process 300 bmay be implemented, at least in part, according to software stored inone or more non-transitory computer readable media. FIGS. 3B and 5-10may be described together below.

At block 350 of the process 300 b, a substrate is heated to an elevatedtemperature. The substrate may be heated to the elevated temperaturebefore and during thermal ALD. This allows the substrate to be heated tothe elevated temperature to drive surface reactions between precursorsand reactants in thermal ALD. In some implementations, the elevatedtemperature applied to the substrate may be between about 500° C. andabout 750° C., between about 500° C. and about 700° C., between about500° C. and about 650° C., or between about 550° C. and about 650° C. Insome implementations, a pressure of a plasma processing chamber may beequal to or greater than about 7 Torr, equal to or greater than about 10Torr, or equal to or greater than about 12 Torr. Chamber pressure mayprovide a further knob to control the deposition rate of the layer ofsilicon oxide film.

In some implementations, prior to heating the substrate to the elevatedtemperature, the substrate may be provided into the plasma processingchamber. The plasma processing chamber may be a single wafer plasmareactor configured to perform thermal ALD processes, PEALD processes, orcombinations thereof. The substrate may be a silicon substrate, such asa 200-mm, 300-mm, or 450-mm substrate, including substrates having oneor more layers of material, such as dielectric, conducting, orsemiconducting material. In some implementations, the substrate on whichsilicon oxide films are deposited may include a material that issensitive to plasma damage by PEALD. For example, the material mayinclude but is not limited to silicon, germanium, silicon-germanium,carbon, and metals, where example metals may include molybdenum,tungsten, copper, cobalt, ruthenium, rhodium, and iridium. The substrateon which the silicon oxide films are deposited may include one or morefeatures such as fins or pillars. In some implementations, the one ormore features may include an under-layer such as a barrier layer, linerlayer, or adhesion layer.

At block 360 of the process 300 b, the substrate is exposed to asilicon-containing precursor to adsorb onto a surface of the substratein the plasma processing chamber. In some implementations, thesilicon-containing precursor includes a silane, such as an aminosilane.An aminosilane includes at least one nitrogen atom bonded to a siliconatom, but may also contain hydrogens, oxygens, halogens and carbons.Examples of aminosilanes may include BTBAS, N-SAM-24, 3DMAS, and 4DMAS.In some implementations, the substrate is exposed to thesilicon-containing precursor while the substrate is heated to theelevated temperature.

FIG. 5 illustrates an example timing sequence diagram showing thermalALD cycles for depositing a silicon oxide film with co-flowed hydrogenand an oxygen-containing reactant according to some implementations. Afirst thermal ALD cycle 510A may include a dose phase 557A, followed bya first purge phase 559A, followed by a thermal oxidation phase 561A,and followed by a second purge phase 563A. A second thermal ALD cycle510B may include a dose phase 557B, followed by a first purge phase559B, followed by a thermal oxidation phase 561B, and followed by asecond purge phase 563B. As shown in FIG. 5, the substrate may beexposed to the silicon-containing precursor during the dose phase557A/557B of the thermal ALD cycle 510A/510B, where a duration of thedose phase 557A/557B may be between about 0.1 seconds and about 60seconds, between about 0.2 seconds and about 6 seconds, or between about0.3 seconds and about 2 seconds, such as about 0.75 seconds, dependingon the flow rate and the substrate surface area. The silicon-containingprecursor adsorbs onto the surface of the substrate in a self-limitingmanner such that once active sites are occupied by thesilicon-containing precursor, little or no additional silicon-containingprecursor will be adsorbed on the surface of the substrate. During thedose phase 557A/557B, plasma is turned off, no oxygen-containingreactant is flowed to the substrate, and a carrier gas may be flowedtowards the substrate.

In some implementations, the plasma processing chamber may be purgedbetween operations of exposing the substrate to the silicon-containingprecursor and flowing hydrogen and an oxygen-containing reactant intothe plasma processing chamber. In addition, the plasma processingchamber may be purged after the flow of hydrogen and oxygen-containingreactant has ceased. Purging may involve a sweep gas, which may be acarrier gas used in other operations/phases or a different gas. Purgingmay remove excess species in the vapor phase that did not adsorb orreact on the surface of the substrate. As shown in FIG. 5, the plasmaprocessing chamber undergoes purging during purge phases 559A, 563A,559B, and 563B. Silicon-containing precursor flow is turned off, plasmais turned off, hydrogen flow is turned off, and oxygen-containingreactant flow is turned off. However, the carrier gas may continue toflow towards the substrate. In some implementations, the purge phases559A, 563A, 559B, and 563B may each include one or more evacuationsub-phases for evacuating the plasma processing chamber. Alternatively,it will be appreciated that each of the purge phases 559A, 563A, 559B,and 563B may be omitted in some implementations. Each purge phase 559A,563A, 559B, and 563B may have a suitable duration, such as between about0 seconds and about 60 seconds or between about 0.01 seconds and about 6seconds.

Returning to FIG. 3B, at block 370 of the process 300 b, hydrogen andoxygen-containing reactant are flowed towards the substrate in theplasma processing chamber. The hydrogen and the oxygen-containingreactant react within the plasma processing chamber, where a layer of asilicon oxide film is formed on the substrate. The hydrogen andoxygen-containing reactant may be flowed simultaneously into the plasmaprocessing chamber. In some implementations, the oxygen-containingreactant includes oxygen or ozone. For example, the oxygen-containingreactant includes oxygen, thereby providing a co-flow of hydrogen andoxygen (H₂/O₂). Without being limited by any theory, the hydrogen andthe oxygen-containing reactant react in situ with one another within theplasma processing chamber in an exothermic reaction. It is possible thatthe reaction between the hydrogen and the oxygen-containing reactantforms water in the exothermic reaction. The exothermic reaction releasesenergy that may drive the thermal oxidation of the adsorbedsilicon-containing precursor to form silicon oxide film. The flow rateof hydrogen and the flow rate of the oxygen-containing reactant may becontrolled according to a desired flow rate ratio to promote thermaloxidation. In some implementations, a flow rate ratio between hydrogenand the oxygen-containing reactant may be equal to or less than about1.2:1, such as between about 0.5:1 and about 1.2:1. In someimplementations, a flow rate of hydrogen may be between about 0 slm andabout 20 slm, between about 1 slm and about 10 slm, between about 2 slmand about 6 slm, greater than about 3 slm, such as about 4 slm. A flowrate of oxygen-containing reactant may be between about 0.5 slm andabout 20 slm, between about 1 slm and about 10 slm, or between about 2slm and about 8 slm, such as about 5 slm.

During the flow of hydrogen and the oxygen-containing reactant, thesubstrate is maintained at the elevated temperature. The substrate is atthe elevated temperature while the hydrogen and oxygen-containingreactant are flowing towards the substrate to drive a reaction with theadsorbed silicon-containing precursor in the plasma processing chamber,thereby forming the layer of the silicon oxide film. The elevatedtemperature may promote formation of the layer of the silicon oxide filmat an appreciable deposition rate. Without being limited by any theory,the in situ exothermic reaction between hydrogen and theoxygen-containing reactant along with the heated substrate at theelevated temperature may provide sufficient energy to drive theformation of the layer of the silicon oxide film at an appreciabledeposition rate. In some implementations, the deposition rate of thelayer of the silicon oxide film using co-flowed hydrogen andoxygen-containing reactant may be equal to or greater than about 0.7Å/cycle.

As shown in FIG. 5, hydrogen and oxygen-containing reactant may beflowed towards the substrate while the substrate is heated at theelevated temperature during a thermal oxidation phase 561A/561B of thethermal ALD cycle 510A/510B. The in situ exothermic reaction between thehydrogen and oxygen-containing reactant combined with the substrateheated at the elevated temperature may provide energy for drivingoxidation during the thermal oxidation phase 561A/561B. Moreover,temperature and pressure in the plasma processing chamber may becontrolled to enable the deposition of the layer of the silicon oxidefilm at a deposition rate equal to or greater than about 0.7 Å/cycleduring the thermal oxidation phase 561A/561B. A duration of the thermaloxidation phase 561A/561B may be between about 0.1 seconds and about 6seconds, between about 0.2 seconds and about 4 seconds, or between about0.5 seconds and about 3 seconds. For example, the duration of thethermal oxidation phase 561A/561B with co-flowed hydrogen andoxygen-containing reactant may be between about 0.5 seconds and about 1second, such as about 0.8 seconds. During the thermal oxidation phase561A/561B, plasma is turned off and silicon-containing precursor flow isturned off. However, carrier gas, hydrogen, and oxygen-containingreactant flow may be turned on.

Example process times and process conditions are shown in Table 1 forco-flowed hydrogen and oxygen in thermal ALD.

TABLE 1 Process Dose 0.2-2 seconds Times Post-Dose Purge 0.15-2 secondsConversion Time 0.5-2 seconds Post-Oxidation Time 0-1 second ProcessSilicon-Containing 1500 sccm Conditions Precursor Flow Purge Gas Flow25000-65000 sccm O2 Flow 2000-5000 sccm H2 flow 2000-5000 sccm Pressure9 Torr-17.5 Torr Temperature 500° C.-750° C.   Purge Gas Ar and/or N2

In some implementations, the process 300 b further includes applyingplasma power to the plasma processing chamber to ignite plasma generatedfrom the hydrogen and oxygen-containing reactant in the plasmaprocessing chamber. In some implementations, the plasma may includeions, radicals, and other reactive species of hydrogen and oxygen (e.g.,H* and O*). In some implementations, the plasma may further includeions, radicals, and other reactive species of the carrier gas (e.g.,Art). The plasma power applied to the plasma processing chamber may berelatively small. In some implementations, the plasma power applied tothe plasma processing chamber is equal to or less than about 300 W,equal to or less than about 200 W, or between about 10 W and about 200W. That way, the plasma may include more radicals and fewer ions. Invarious implementations, the RF frequency used to generate the plasmamay be at least about 13.56 MHz, at least about 27 MHz, at least about40 MHz, or at least about 60 MHz, though other frequencies may also beused.

Without being limited by any theory, low RF power may ignite low RFplasma with energy from the exothermic reaction between the hydrogen andthe oxygen-containing reactant. Without an in situ exothermic reactionbetween hydrogen and the oxygen-containing reactant, plasma may not beignited at relatively low RF powers. In other words, a combustionreaction of hydrogen and the oxygen-containing reactant may contributeto generating low RF plasma in the plasma processing chamber. A stableplasma may be maintained at relatively low RF powers. The low RF plasmamay limit damage to the substrate and particularly limit damage to anysensitive substrate. The low RF plasma may enhance or at least modulatedeposition and properties of the layer of silicon oxide film. In someimplementations, the low RF plasma may modulate deposition rate andprovide higher wet etch rates. In some implementations, the low RFplasma may provide more conformal films, lower operating temperatures,and/or higher deposition rates.

FIG. 6 illustrates an example timing sequence diagram showing thermalALD cycles for depositing a silicon oxide film with low RF plasma poweraccording to some implementations. FIG. 6 shows a first thermal ALDcycle 610A that includes a dose phase 657A, first purge phase 659A,thermal oxidation phase 661A, and second purge phase 663A. FIG. 6 alsoshows a second thermal ALD cycle 610B that includes a dose phase 657B,first purge phase 659B, thermal oxidation phase 661B, and second purgephase 663B. Aspects of the phases for each of the thermal ALD cycles610A/610B of FIG. 6 can be described in the thermal ALD cycles 510A/510Bof FIG. 5.

In the thermal oxidation phase 661A/661B, plasma is turned on ratherthan off. The plasma power can be a low RF plasma power that is equal toor less than about 300 W, equal to or less than about 200 W, or betweenabout 10 W and about 200 W. Application of the low RF plasma poweroccurs while hydrogen and oxygen-containing reactant are being flowedtoward the substrate and while the substrate is heated at the elevatedtemperature. Reactive species in the plasma such as radicals of oxygenmay react with the adsorbed silicon-containing precursor to form siliconoxide.

In some implementations at block 370 of the process 300 b, flowinghydrogen and oxygen-containing reactant towards the substrate mayinclude flowing the oxygen-containing reactant continuously into theplasma processing chamber and pulsing hydrogen at regular intervals intothe plasma processing chamber. The hydrogen may be pulsed at regularintervals while the oxygen-containing reactant is simultaneously andcontinuously flowed towards the substrate. For example, a constantoxygen flow may be combined with pulsed hydrogen flow into the plasmaprocessing chamber. In some implementations, pulses of hydrogen may beintroduced into the plasma processing chamber at regular intervals thatlast between about 0.1 seconds and about 1 second, between about 0.1seconds and about 0.8 seconds, or between about 0.2 seconds and about0.6 seconds. Pulsing hydrogen may facilitate combustion reactions ofhydrogen and oxygen-containing reactant that occur in pulses rather thancontinuously. Pulsing hydrogen may affect the deposition and propertiesof the layer of silicon oxide film. When pulsing hydrogen, the durationof the thermal oxidation phase may be longer. Without being limited byany theory, this permits pulsed exothermic reaction(s) to proceed for aslong as desired to drive film properties.

FIG. 7 illustrates an example timing sequence diagram showing thermalALD cycles for depositing a silicon oxide film with pulsing hydrogenflow during oxidation according to some implementations. FIG. 7 shows afirst thermal ALD cycle 710A that includes a dose phase 757A, firstpurge phase 759A, thermal oxidation phase 761A, and second purge phase763A. FIG. 7 also shows a second thermal ALD cycle 710B that includes adose phase 757B, first purge phase 759B, thermal oxidation phase 761B,and second purge phase 763B. Aspects of the phases for each of thethermal ALD cycles 710A/710B of FIG. 7 can be described in the thermalALD cycles 510A/510B of FIG. 5.

In the thermal oxidation phase 761A/761B, hydrogen flow is pulsed ratherthan continuous. Oxygen-containing reactant flow is continuous andsimultaneous with the pulsed hydrogen flow. Typically, pulses in thepulsed hydrogen flow can be in the form of a square waveform. The pulsesin the pulsed hydrogen flow can occur in regular intervals, where eachof the regular intervals can last between about 0.1 seconds and about 1second, between about 0.1 seconds and about 0.8 seconds, or betweenabout 0.2 seconds and about 0.6 seconds. In some implementations, atotal duration of the thermal oxidation phase 761A/761B may be equal toor greater than 0.5 seconds, equal to or greater than 1 second, orbetween about 1 second and about 30 seconds. It will be understood thatthe total duration of the thermal oxidation phase 761A/761B may belonger to permit pulsed exothermic reactions to drive film properties. Aduty cycle can refer to the percentage of on time (T_(on)) that flow isturned on during the total of on and off time, where T=T_(on)+T_(off)during the thermal oxidation phase 761A/761B. In some implementations,the duty cycle of the pulsed hydrogen flow can be between about 1% andabout 99%, between about 5% and about 95%, between about 15% and about90%, or between about 25% and about 75%.

In some implementations at block 370 of the process 300 b, flowinghydrogen and oxygen-containing reactant towards the substrate mayinclude generating oxygen radicals from the oxygen-containing reactantin a remote plasma source, introducing the radicals of oxygen into theplasma processing chamber, and flowing the hydrogen into the plasmaprocessing chamber. Instead of pure oxygen gas, the radicals of oxygenmay provide more reactive species to react with the hydrogen and theadsorbed silicon-containing precursor. Without being limited by anytheory, the radicals of oxygen may react with hydrogen to form hydroxylradicals or water, where the hydroxyl radicals or water may promoteoxidation of the adsorbed silicon-containing precursor. In someimplementations, the oxygen radicals are generated from oxygen gas orozone. In some implementations, remote plasma source is located upstreamof the plasma processing chamber, where the remote plasma source can beany suitable plasma generator such as an inductively-coupled plasmagenerator or capacitively-coupled plasma generator.

FIG. 8 illustrates an example timing sequence diagram showing thermalALD cycles for depositing a silicon oxide film with oxygen radicalsgenerated from a remote plasma source during oxidation according to someimplementations. FIG. 8 shows a first thermal ALD cycle 810A thatincludes a dose phase 857A, first purge phase 859A, thermal oxidationphase 861A, and second purge phase 863A. FIG. 8 also shows a secondthermal ALD cycle 810B that includes a dose phase 857B, first purgephase 859B, thermal oxidation phase 861B, and second purge phase 863B.Aspects of the phases for each of the thermal ALD cycles 810A/810B ofFIG. 8 can be described in the thermal ALD cycles 510A/510B of FIG. 5.

In the thermal oxidation phase 861A/861B, oxygen radicals are introducedinto the plasma processing chamber instead of pure oxygen gas. Hydrogenflow may be continuous and simultaneous with the flow of oxygen radicalsinto the plasma processing chamber. However, it will be understood thatin some implementations, hydrogen flow may be pulsed. In the thermaloxidation phase 861A/861B, remote plasma power is turned on rather thanoff. RF power may be applied to a remote plasma source to generate theoxygen radicals upstream from the plasma processing chamber.

In some implementations, at block 380 of the process 300 b, the process300 b further includes performing PEALD in the plasma processingchamber. For example, the process 300 b can include depositing one ormore additional layers of the silicon oxide film on the substrate viaPEALD in the plasma processing chamber. In addition or in thealternative, the process 300 b can include depositing one or more layersof a silicon nitride film on the layer of the silicon oxide film bythermal ALD or PEALD in the plasma processing chamber to ultimately forma silicon oxynitride film. In some implementations, at block 380 of theprocess 300 b, a PEALD cycle can include exposing the substrate toplasma of a nitrogen-containing reactant to convert the layer of thesilicon oxide film to a silicon oxynitride film during a plasma exposurephase. The layer of silicon oxide film deposited by thermal ALD mayserve as a liner layer protecting underlying layers of the substrate,and subsequent layers of silicon oxide and/or silicon nitride may bedeposited in bulk over the liner layer. The layer of silicon oxide filmdeposited by thermal ALD may exhibit high conformality, high depositionrate, limited surface oxidation, limited bending of substrate features(e.g., pillars, fins), and uniform wet etch rate on sidewalls. In someimplementations, however, performing PEALD in the plasma processingchamber may occur before thermal ALD in the plasma processing chamber.In other words, layers of silicon oxide film may be deposited by PEALDand followed by additional layers of silicon oxide film deposited bythermal ALD.

FIG. 9 illustrates an example timing sequence diagram showing a thermalALD cycle with co-flowed hydrogen and oxygen followed by a PEALD cyclewith plasma oxidation/nitridation for depositing a silicon-containingfilm according to some implementations. However, it will be understoodthat the PEALD cycle may be performed prior to the thermal ALD cycle insome implementations. FIG. 9 shows a thermal ALD cycle 910A thatincludes a dose phase 957A, a first purge phase 959A, a thermaloxidation phase 961A, and a second purge phase 963A. FIG. 9 also shows aPEALD cycle 910B that includes a dose phase 957B, first purge phase959B, plasma oxidation/nitridation phase 961B, and second purge phase963B. Aspects of the phases for the thermal ALD cycle 910A of FIG. 9 canbe described in the thermal ALD cycle 510A/510B of FIG. 5. Aspects ofthe phases for the PEALD cycle 910B of FIG. 9 can be described in thePEALD cycle 410B of FIG. 4.

In the plasma oxidation/nitridation phase 961B, the substrate may beexposed to an oxygen plasma or nitrogen plasma. If plasma nitridationtakes place, one or more nitrogen-containing reactants may be flowedtowards the substrate and plasma turned on. For example, the one or morenitrogen-containing reactants may include N₂/NH₃. The plasma nitridationmay deposit a layer of silicon nitride film over the layer of siliconoxide film. In some implementations, the plasma nitridation may convertsilicon oxide to silicon oxynitride. If plasma oxidation takes place,one or more oxygen-containing reactants maybe flowed towards thesubstrate and plasma turned on. For example, the one or moreoxygen-containing reactants may include O₂. The plasma oxidation maydeposit an additional layer of silicon oxide film over the layer ofsilicon oxide film.

In some implementations, at blocks 360 and 370 of the process 300 b,exposing the substrate to the silicon-containing precursor and flowingthe hydrogen and oxygen-containing reactant may occur in a continuousmanner rather than in a cyclic manner Specifically, exposing thesubstrate to the silicon-containing precursor and flowing the hydrogenand oxygen-containing reactant occurs in a thermal CVD process insteadof a thermal ALD process. Briefly, thermal ALD reactions involvecyclically performing (a) delivery of precursor to form an adsorbedprecursor layer, (b) optional purge operation, (c) delivery ofreactant(s) on a heated substrate, (d) optional purge operation, and (e)repeating operations (a)-(d) until the film reaches a desired thickness.However, thermal CVD reactions involve delivering the precursor andreactant(s) continuously while the substrate is heated. CVD reactionsare gas phase reactions, which deposition reaction products on thesubstrate surface. Hence, the reaction mechanism of the presentdisclosure may involve thermal CVD using silicon-containing precursor,hydrogen, and oxygen-containing reactant being delivered continuouslyrather than cyclically in thermal ALD.

FIG. 10 illustrates an example timing sequence diagram showing thermalCVD with co-flowed silicon-containing precursor, hydrogen, andoxygen-containing reactant for depositing a silicon-containing filmaccording to some implementations. A thermal CVD process 1010 is notbroken down into a series of phases in cycles. Carrier gas iscontinuously flowed to the substrate, silicon-containing precursor iscontinuously flowed to the substrate, hydrogen gas is continuouslyflowed to the substrate, and oxygen-containing reactant is continuouslyflowed to the substrate. Delivery of the silicon-containing precursor,delivery of hydrogen, and delivery of the oxygen-containing reactant donot occur sequentially and do not occur in separate phases. Plasma isturned off during the thermal CVD process 1010.

It will be understood that any of the foregoing techniques described inFIGS. 4-10 may be mixed together in a series of ALD cycles and/or CVDreactions. In other words, deposition of a silicon-containing film bythermal ALD may involve one or more cycles with pulsed hydrogen flow,one or more cycles with co-flowed hydrogen and oxygen-containingreactant, one or more cycles with application of low RF power, one ormore cycles with oxygen radicals, one or more PEALD cycles for plasmaoxidation/nitridation, and one or more periods of thermal CVD reactionswith a silicon-containing precursor, hydrogen, and oxygen-containingreactant. Such techniques may be applied in any sequence when depositingthe silicon-containing film.

Apparatus

The methods described herein may be performed by any suitable apparatusor combination of apparatus. A suitable apparatus includes hardware foraccomplishing the process operations and a system controller havinginstructions for controlling process operations in accordance with thepresent disclosure. For example, in some implementations, the hardwaremay include one or more process stations included in a process tool. Inthe present disclosure, the thermal ALD/CVD and PEALD/PECVD may beperformed in a single station/chamber.

FIG. 11 is a schematic diagram of an example plasma processing apparatusfor depositing a silicon-containing film using thermal ALD according tosome implementations. The plasma apparatus or process station 1100 aincludes a plasma processing chamber 1102 for maintaining a low-pressureenvironment. A plurality of plasma apparatuses or process stations 1100a may be included in a common low-pressure process tool environment. Forexample, FIG. 12 depicts an implementation of a multi-station processingtool 1200. In some implementations, one or more hardware parameters ofthe plasma apparatus or process station 1100 a including those discussedin detail below may be adjusted programmatically by one or more systemcontrollers 1150. The plasma apparatus or process station 1100 a can beconfigured to perform thermal ALD and PEALD, thermal CVD and PEALD,thermal ALD and PECVD, or thermal CVD and PECVD. In someimplementations, the plasma apparatus or process station 1100 a can beconfigured to perform one or more PEALD cycles and one or more thermalALD cycles to deposit a silicon oxide film on a substrate 1112.

The apparatus or process station 1100 a fluidly communicates withreactant delivery system 1101 a for delivering process gases to adistribution showerhead 1106. Reactant delivery system 1101 a includes amixing vessel 1104 for blending and/or conditioning process gases, suchas a silicon-containing precursor in the vapor phase, for delivery toshowerhead 1106. In some implementations, the reactant delivery system1101 a includes a mixing vessel 1104 for blending and/or conditioning anoxygen-containing reactant (e.g., oxygen) for delivery to the showerhead1106. In some implementations, the reactant delivery system 1101 aincludes a mixing vessel 1104 for blending and/or conditioning hydrogenand an oxygen-containing reactant (e.g., oxygen) for delivery to theshowerhead 1106. One or more mixing vessel inlet valves 1120 may controlintroduction of process gases to mixing vessel 1104. Plasma of theoxygen-containing reactant may also be delivered to the showerhead 1106or may be generated in the plasma apparatus or process station 1100 a.The showerhead 1106 may be fluidly coupled to the plasma processingchamber 1102 for delivery of silicon-containing precursors and reactantsinto the plasma processing chamber 1102.

As an example, the implementation of FIG. 11 includes a vaporizationpoint 1103 for vaporizing liquid reactant to be supplied to the mixingvessel 1104. In some implementations, vaporization point 1103 may be aheated vaporizer. In some implementations, delivery piping downstream ofvaporization point 1103 may be heat traced. In some examples, the mixingvessel 1104 may also be heat traced. In one non-limiting example, pipingdownstream of vaporization point 1103 has an increasing temperatureprofile extending from approximately 100° C. to approximately 150° C. atthe mixing vessel 1104. In some implementations, liquid precursor orliquid reactant may be vaporized at a liquid injector. For example, aliquid injector may inject pulses of a liquid reactant into a carriergas stream upstream of the mixing vessel 1104. In one implementation, aliquid injector may vaporize the reactant by flashing the liquid from ahigher pressure to a lower pressure. In another example, a liquidinjector may atomize the liquid into dispersed microdroplets that aresubsequently vaporized in a heated delivery pipe. Smaller droplets mayvaporize faster than larger droplets, reducing a delay between liquidinjection and complete vaporization. Faster vaporization may reduce alength of piping downstream from vaporization point 1103. In onescenario, a liquid injector may be mounted directly to mixing vessel1104. In another scenario, a liquid injector may be mounted directly toshowerhead 1106.

In some implementations, a liquid flow controller (LFC) upstream ofvaporization point 1103 may be provided for controlling a mass flow ofliquid for vaporization and delivery to the plasma apparatus or processstation 1100 a. For example, the LFC may include a thermal mass flowmeter (MFM) located downstream of the LFC. A plunger valve of the LFCmay then be adjusted responsive to feedback control signals provided bya proportional-integral-derivative (PID) controller in electricalcommunication with the MFM. However, it may take one second or more tostabilize liquid flow using feedback control. This may extend a time fordosing a liquid reactant. Thus, in some implementations, the LFC may bedynamically switched between a feedback control mode and a directcontrol mode. In some implementations, this may be performed bydisabling a sense tube of the LFC and the PID controller.

The showerhead 1106 distributes process gases toward a substrate 1112.In the implementation shown in FIG. 11, the substrate 1112 is locatedbeneath the showerhead 1106 and is shown resting on a substrate support1108, where the substrate support 1108 is configured to support thesubstrate 1112. The substrate support 1108 may include a chuck, a fork,or lift pins (not shown) to hold and transfer the substrate 1112 duringand between the deposition operations. The chuck may be an electrostaticchuck, a mechanical chuck, or various other types of chuck as areavailable for use in the industry and/or for research. The showerhead1106 may have any suitable shape, and may have any suitable number andarrangement of ports for distributing process gases to the substrate1112.

In some implementations, the substrate support 1108 may be raised orlowered to expose the substrate 1112 to a volume between the substrate1112 and the showerhead 1106. It will be appreciated that, in someimplementations, substrate support height may be adjustedprogrammatically by a suitable system controller 1150.

In another scenario, adjusting a height of the substrate support 1108may allow a plasma density to be varied during plasma activation cyclesincluded in the process. At the conclusion of a processing phase, thesubstrate support 1108 may be lowered during another substrate transferphase to allow removal of the substrate 1112 from the substrate support1108.

In some implementations, the substrate support 1108 may be configured tobe heated to an elevated temperature via a heater 1110. In someimplementations, the substrate support 1108 may be heated to atemperature less than about 700° C., such as about between about 500° C.and about 750° C. or between about 500° C. and about 650° C., duringdeposition of silicon oxide films as described in the disclosedimplementations. Further, in some implementations, pressure control forthe apparatus or process station 700 a may be provided by a butterflyvalve 1118. As shown in the implementation of FIG. 11, the butterflyvalve 1118 throttles a vacuum provided by a downstream vacuum pump (notshown). However, in some implementations, pressure control of the plasmaprocessing chamber 1102 may also be adjusted by varying a flow rate ofone or more gases introduced to the plasma processing chamber 1102.

In some implementations, the pressure in the plasma processing chamber1102 may be controlled to be equal to or greater than about 7 Torr,equal to or greater than about 10 Torr, or equal to or greater thanabout 12 Torr during deposition of silicon oxide films as described inthe disclosed implementations.

In some implementations, a position of the showerhead 1106 may beadjusted relative to the substrate support 1108 to vary a volume betweenthe substrate 1112 and the showerhead 1106. Further, it will beappreciated that a vertical position of substrate support 1108 and/orshowerhead 1106 may be varied by any suitable mechanism within the scopeof the present disclosure. In some implementations, the substratesupport 1108 may include a rotational axis for rotating an orientationof the substrate 1112. It will be appreciated that, in someimplementations, one or more of these example adjustments may beperformed programmatically by one or more suitable system controllers1150.

In some implementations where plasma may be used as discussed above,showerhead 1106 and substrate support 1108 electrically communicate witha radio frequency (RF) power supply 1114 and matching network 1116 forpowering a plasma in the plasma processing chamber 1102. In someimplementations, the plasma energy may be controlled by controlling oneor more of a process station pressure, a gas concentration, an RF sourcepower, an RF source frequency, and a plasma power pulse timing. Forexample, RF power supply 1114 and matching network 1116 may be operatedat any suitable power to form a plasma having a desired composition ofradical species. In some implementations, the RF power supply 1114 andmatching network 1116 may be operated to apply plasma power to theplasma processing chamber 1102 to ignite plasma generated from hydrogenand oxygen-containing reactant in the plasma processing chamber 1102.Example plasma powers applied by the RF power supply 1114 may be equalto or less than about 300 W, equal to or less than about 200 W, orbetween about 10 W and about 200 W. Likewise, RF power supply 1114 mayprovide RF power of any suitable frequency. In some implementations, RFpower supply 1114 may be configured to control high- and low-frequencyRF power sources independently of one another. Example low-frequency RFfrequencies may include, but are not limited to, frequencies between 0kHz and 500 kHz. Example high-frequency RF frequencies may include, butare not limited to, frequencies between 1.8 MHz and 2.45 GHz, or atleast about 13.56 MHz, or at least about 27 MHz, or at least about 40MHz, or at least about 60 MHz. It will be appreciated that any suitableparameters may be modulated discretely or continuously to provide plasmaenergy for the surface reactions.

In some implementations, the plasma may be monitored in-situ by one ormore plasma monitors. In one scenario, plasma power may be monitored byone or more voltage, current sensors (e.g., VI probes). In anotherscenario, plasma density and/or process gas concentration may bemeasured by one or more optical emission spectroscopy sensors (OES). Insome implementations, one or more plasma parameters may beprogrammatically adjusted based on measurements from such in situ plasmamonitors. For example, an OES sensor may be used in a feedback loop forproviding programmatic control of plasma power. It will be appreciatedthat, in some implementations, other monitors may be used to monitor theplasma and other process characteristics. Such monitors may include, butare not limited to, infrared (IR) monitors, acoustic monitors, andpressure transducers.

In some implementations, instructions for a controller 1150 may beprovided via input/output control (IOC) sequencing instructions. In oneexample, the instructions for setting conditions for a process phase maybe included in a corresponding recipe phase of a process recipe. In somecases, process recipe phases may be sequentially arranged, so that allinstructions for a process phase are executed concurrently with thatprocess phase. In some implementations, instructions for setting one ormore reactor parameters may be included in a recipe phase. For example,a first recipe phase may include instructions for setting a flow rate ofan inert and/or a precursor gas (e.g., the silicon-containingprecursor), instructions for setting a flow rate of a carrier gas (suchas argon), and time delay instructions for the first recipe phase. Asecond, subsequent recipe phase may include instructions for modulatingor stopping a flow rate of an inert and/or a precursor gas, andinstructions for modulating a flow rate of a carrier or purge gas andtime delay instructions for the second recipe phase. A third recipephase may include instructions for modulating a flow rate of anoxygen-containing reactant gas such as oxygen, instructions formodulating a flow rate of hydrogen gas, instructions for modulating theflow rate of a carrier or purge gas, and time delay instructions for thethird recipe phase. A fourth, subsequent recipe phase may includeinstructions for modulating or stopping a flow rate of an inert and/or areactant gas, and instructions for modulating a flow rate of a carrieror purge gas and time delay instructions for the fourth recipe phase.The fourth recipe, in some implementations, may include instructions forigniting plasma of the oxygen-containing reactant. It will beappreciated that these recipe phases may be further subdivided and/oriterated in any suitable way within the scope of the disclosedimplementations.

In certain implementations, the controller 1150 has instructions toperform the operations described in the present disclosure. For example,the controller 1150 may be configured with instructions to perform thefollowing operations: expose a substrate 1112 to a silicon-containingprecursor to adsorb onto a surface of the substrate 1112 in the plasmaprocessing chamber 1102, flow hydrogen and oxygen-containing reactanttowards the substrate 1112 in the plasma processing chamber 1102, andheat the substrate 1112 to an elevated temperature, where the hydrogenand oxygen-containing reactant react with one another in the plasmaprocessing chamber 1102, where a layer of silicon oxide film is formedon the substrate 1112. In some implementations, the elevated temperatureis between about 500° C. and about 650° C. and the oxygen-containingreactant is oxygen. In some implementations, the controller 1150 isfurther configured with instructions to perform the following operation:deposit one or more additional layers of the silicon oxide film on thesubstrate 1112 via PEALD in the plasma processing chamber 1102. In someimplementations, the controller 1150 configured with instructions forflowing the hydrogen and oxygen-containing reactant is configured withinstructions for performing the following operations: flow theoxygen-containing reactant continuously into the plasma processingchamber 1102, and pulse hydrogen at regular intervals into the plasmaprocessing chamber 1102. In some implementations, the controller 1150may include any of the features described below with respect to systemcontroller 1250 of FIG. 12.

FIG. 12 is a schematic diagram of an example process tool for performingthe disclosed implementations. A multi-station processing tool 1200 mayinclude a transfer module 1203. The transfer module 1203 provides aclean, pressurized environment to minimize the risk of contamination ofsubstrates being processed as they are moved between various reactormodules. Mounted on the transfer module 1203 are multi-station reactors1207, 1208, and 1209, referred to in this context as processing chambersor reactors or tool modules or modules. Each reactor is capable ofperforming deposition processes such as PEALD, thermal ALD, PECVD, orthermal CVD. One or more of the reactors 1207, 1208, and 1209 may becapable of performing soaking/cleaning, plasma treatment, etching,annealing, or other operations. The reactors 1207, 1208, and 1209 mayinclude multiple stations 1211, 1213, 1215, and 1217 that maysequentially or non-sequentially perform operations in accordance withthe disclosed implementations. While a depicted reactor 1207, 1208, or1209 is depicted with four stations, it will be understood that areactor according to the present disclosure may have any suitable numberof stations. For example, in some implementations, a reactor may havefive or more stations, while in other implementations, a reactor mayhave three or fewer stations. Each station may be configured fordeposition by PEALD, thermal ALD, PECVD, or thermal CVD, or configuredfor different phases of a deposition process. Each station may include asubstrate support configured to be heated to an elevated temperature aswell as a showerhead or gas inlets for delivering gases.

The multi-station processing tool 1200 also includes one or moresubstrate source modules 1201 where substrates are stored before andafter processing. An atmospheric robot 1204 in the atmospheric transferchamber 1219 first removes substrates from the one or more substratesource modules 1201 to load locks 1221. While the implementationdepicted includes load locks 1221, it will be appreciated that, in someimplementations, direct entry of a substrate into a process station maybe provided. A substrate transfer device 1205, such as a robot arm unit,in the transfer module 1203 moves the substrates from the load locks1221 to and among the reactors 1207, 1208, and 1209. This can be done ina pressurized (e.g., vacuum) environment. The multi-station processingtool 1200 may perform one or more of the processes described in thepresent disclosure as well as other operations such as soaking/cleaning,plasma treatment, annealing, etc. Such processes may be performed in themulti-station processing tool 1200 without introducing a vacuum break.

FIG. 12 may also include a system controller 1250 employed to controlprocess conditions and hardware states of multi-station processing tool1200. System controller 1250 may include one or more memory devices, oneor more mass storage devices, and one or more processors. Processor mayinclude a CPU or computer, analog and/or digital input/outputconnections, stepper motor controller boards, etc.

In some implementations, a controller is part of a system, which may bepart of the above-described examples. Such systems can comprisesemiconductor processing equipment, including a processing tool ortools, chamber or chambers, a platform or platforms for processing,and/or specific processing components (a wafer pedestal, a gas flowsystem, etc.). These systems may be integrated with electronics forcontrolling their operation before, during, and after processing of asemiconductor wafer or substrate. The electronics may be referred to asthe “controller,” which may control various components or subparts ofthe system or systems. The controller, depending on the processingrequirements and/or the type of system, may be programmed to control anyof the processes disclosed herein, including the delivery of processinggases, temperature settings (e.g., heating and/or cooling), pressuresettings, vacuum settings, power settings, radio frequency (RF)generator settings, RF matching circuit settings, frequency settings,flow rate settings, fluid delivery settings, positional and operationsettings, wafer transfers into and out of a tool and other transfertools and/or load locks connected to or interfaced with a specificsystem.

Broadly speaking, the controller may be defined as electronics havingvarious integrated circuits, logic, memory, and/or software that receiveinstructions, issue instructions, control operation, enable cleaningoperations, enable endpoint measurements, and the like. The integratedcircuits may include chips in the form of firmware that store programinstructions, digital signal processors (DSPs), chips defined asapplication specific integrated circuits (ASICs), and/or one or moremicroprocessors, or microcontrollers that execute program instructions(e.g., software). Program instructions may be instructions communicatedto the controller in the form of various individual settings (or programfiles), defining operational parameters for carrying out a particularprocess on or for a semiconductor wafer or to a system. The operationalparameters may, in some implementations, be part of a recipe defined byprocess engineers to accomplish one or more processing operations duringthe fabrication of one or more layers, materials, metals, oxides,silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.

The controller, in some implementations, may be a part of or coupled toa computer that is integrated with, coupled to the system, otherwisenetworked to the system, or a combination thereof. For example, thecontroller may be in the “cloud” or all or a part of a fab host computersystem, which can allow for remote access of the wafer processing. Thecomputer may enable remote access to the system to monitor currentprogress of fabrication operations, examine a history of pastfabrication operations, examine trends or performance metrics from aplurality of fabrication operations, to change parameters of currentprocessing, to set processing operations to follow a current processing,or to start a new process. In some examples, a remote computer (e.g. aserver) can provide process recipes to a system over a network, whichmay include a local network or the Internet. The remote computer mayinclude a user interface that enables entry or programming of parametersand/or settings, which are then communicated to the system from theremote computer. In some examples, the controller receives instructionsin the form of data, which specify parameters for each of the processingoperations to be performed during one or more operations. It should beunderstood that the parameters may be specific to the type of process tobe performed and the type of tool that the controller is configured tointerface with or control. Thus as described above, the controller maybe distributed, such as by comprising one or more discrete controllersthat are networked together and working towards a common purpose, suchas the processes and controls described herein. An example of adistributed controller for such purposes would be one or more integratedcircuits on a chamber in communication with one or more integratedcircuits located remotely (such as at the platform level or as part of aremote computer) that combine to control a process on the chamber.

Without limitation, example systems may include a plasma etch chamber ormodule, a deposition chamber or module, a spin-rinse chamber or module,a metal plating chamber or module, a clean chamber or module, a beveledge etch chamber or module, a physical vapor deposition (PVD) chamberor module, a chemical vapor deposition (CVD) chamber or module, anatomic layer deposition (ALD) chamber or module, an atomic layer etch(ALE) chamber or module, an ion implantation chamber or module, a trackchamber or module, and any other semiconductor processing systems thatmay be associated or used in the fabrication and/or manufacturing ofsemiconductor wafers.

As noted above, depending on the process operation or operations to beperformed by the tool, the controller might communicate with one or moreof other tool circuits or modules, other tool components, cluster tools,other tool interfaces, adjacent tools, neighboring tools, tools locatedthroughout a factory, a main computer, another controller, or tools usedin material transport that bring containers of wafers to and from toollocations and/or load ports in a semiconductor manufacturing factory.

Returning to the implementation of FIG. 12, in some implementations,system controller 1250 controls all of the activities of multi-stationprocessing tool 1200. System controller 1250 executes system controlsoftware stored in mass storage device, loaded into memory device, andexecuted on processor. Alternatively, the control logic may be hardcoded in the controller 1250. Applications Specific Integrated Circuits,Programmable Logic Devices (e.g., field-programmable gate arrays, orFPGAs) and the like may be used for these purposes. In the followingdiscussion, wherever “software” or “code” is used, functionallycomparable hard coded logic may be used in its place. System controlsoftware 1258 may include instructions for controlling the timing,mixture of gases, chamber and/or station pressure, chamber and/orstation temperature, wafer temperature, target power levels, RF powerlevels, RF exposure time, substrate pedestal, chuck and/or susceptorposition, and other parameters of a particular process performed bymulti-station processing tool 1200. System control software may beconfigured in any suitable way. For example, various process toolcomponent subroutines or control objects may be written to controloperation of the process tool components necessary to carry out variousprocess tool processes. System control software may be coded in anysuitable computer readable programming language.

In some implementations, system control software may includeinput/output control (IOC) sequencing instructions for controlling thevarious parameters described above. For example, each phase of a thermalALD cycle or each phase of a PEALD cycle may include one or moreinstructions for execution by system controller 1250. The instructionsfor setting process conditions for an ALD process phase may be includedin a corresponding ALD recipe phase. In some implementations, the ALDrecipe phases may be sequentially arranged, so that all instructions foran ALD process phase are executed concurrently with that process phase.

Other computer software and/or programs stored on mass storage deviceand/or memory device associated with system controller 1250 may beemployed in some implementations. Examples of programs or sections ofprograms for this purpose include a substrate positioning program, aprocess gas control program, a pressure control program, a heatercontrol program, and a plasma control program.

A substrate positioning program may include program code for processtool components that are used to load the substrate onto pedestal and tocontrol the spacing between the substrate and other parts ofmulti-station processing tool 1200.

A process gas control program may include code for controlling gascomposition and flow rates and optionally for flowing gas into one ormore process stations prior to deposition in order to stabilize thepressure in the process station. In some implementations, the controllerincludes instructions for depositing a first silicon oxide layer bythermal ALD in a plasma processing chamber, and depositing a secondsilicon oxide layer by PEALD in the same plasma processing chamber. Insome implementations, the controller includes instructions fordepositing a layer of silicon oxide by delivering silicon-containingprecursor to a substrate in a dose phase and co-flowing hydrogen andoxygen towards the substrate in a thermal oxidation phase.

A pressure control program may include code for controlling the pressurein the process station by regulating, for example, a throttle valve inthe exhaust system of the process station, a gas flow into the processstation, etc. In some implementations, the controller includesinstructions for providing a chamber pressure in the plasma processingchamber to be at least about 7 Torr prior to performing thermal ALD ofsilicon oxide layer.

A heater control program may include code for controlling the current toa heating unit that is used to heat the substrate. Alternatively, theheater control program may control delivery of a heat transfer gas (suchas helium) to the substrate. In certain implementations, the controllerincludes instructions for heating the substrate to an elevatedtemperature during a thermal oxidation phase of a thermal ALD cycle,where the elevated temperature is between about 500° C. and about 650°C.

A plasma control program may include code for setting RF power levelsand exposure times in one or more process stations in accordance withthe implementations herein. In some implementations, the controllerincludes instructions for igniting plasma at an RF power level betweenabout 10 W and about 200 W during a thermal oxidation phase of a thermalALD cycle when hydrogen and oxygen are being co-flowed.

In some implementations, there may be a user interface associated withsystem controller 1250. The user interface may include a display screen,graphical software displays of the apparatus and/or process conditions,and user input devices such as pointing devices, keyboards, touchscreens, microphones, etc.

In some implementations, parameters adjusted by system controller 1250may relate to process conditions. Non-limiting examples include processgas composition and flow rates, temperature, pressure, plasma conditions(such as RF power levels and exposure times), etc. These parameters maybe provided to the user in the form of a recipe, which may be enteredutilizing the user interface.

Signals for monitoring the process may be provided by analog and/ordigital input connections of system controller 1250 from various processtool sensors. The signals for controlling the process may be output onthe analog and digital output connections of multi-station processingtool 1200. Non-limiting examples of process tool sensors that may bemonitored include mass flow controllers, pressure sensors (such asmanometers), thermocouples, etc. Appropriately programmed feedback andcontrol algorithms may be used with data from these sensors to maintainprocess conditions.

System controller 1250 may provide program instructions for implementingthe above-described deposition processes. The program instructions maycontrol a variety of process parameters, such as DC power level, RF biaspower level, pressure, temperature, gas flow composition, flow rates,etc. The instructions may control the parameters to operate thermal ALDor thermal CVD of silicon oxide film according to variousimplementations described herein.

The system controller 1250 will typically include one or more memorydevices and one or more processors configured to execute theinstructions so that the apparatus will perform a method in accordancewith the disclosed implementations. Machine-readable, non-transitorymedia containing instructions for controlling process operations inaccordance with the disclosed implementations may be coupled to thesystem controller.

The various hardware and method implementations described above may beused in conjunction with lithographic patterning tools or processes, forexample, for the fabrication or manufacture of semiconductor devices,displays, LEDs, photovoltaic panels and the like. Typically, though notnecessarily, such tools/processes will be used or conducted together ina common fabrication facility.

CONCLUSION

In the foregoing description, numerous specific details are set forth toprovide a thorough understanding of the presented embodiments. Thedisclosed embodiments may be practiced without some or all of thesespecific details. In other instances, well-known process operations havenot been described in detail to not unnecessarily obscure the disclosedembodiments. While the disclosed embodiments are described inconjunction with the specific embodiments, it will be understood that itis not intended to limit the disclosed embodiments.

Although the foregoing embodiments have been described in some detailfor purposes of clarity of understanding, it will be apparent thatcertain changes and modifications may be practiced within the scope ofthe appended claims. It should be noted that there are many alternativeways of implementing the processes, systems, and apparatus of thepresent embodiments. Accordingly, the present embodiments are to beconsidered as illustrative and not restrictive, and the embodiments arenot to be limited to the details given herein.

1. A method of depositing a silicon oxide film, the method comprising:providing a substrate in a plasma processing chamber; depositing a firstsilicon oxide layer on a substrate via thermal atomic layer deposition(thermal ALD) in the plasma processing chamber; and depositing a secondsilicon oxide layer on the substrate via plasma-enhanced atomic layerdeposition (PEALD) in the plasma processing chamber.
 2. The method ofclaim 1, wherein depositing the first silicon oxide layer by thermal ALDcomprises: heating the substrate to an elevated temperature; exposingthe substrate to a silicon-containing precursor to adsorb onto a surfaceof the substrate; and exposing the substrate to an oxygen-containingreactant while the substrate is heated to the elevated temperature todrive a reaction between the oxygen-containing reactant and thesilicon-containing precursor to form the first silicon oxide layer. 3.The method of claim 2, wherein the elevated temperature is between about500° C. and about 750° C.
 4. The method of claim 2, wherein theoxygen-containing reactant includes oxygen (O₂), ozone (O₃), hydrogenperoxide (H₂O₂), water (H₂O), or combinations thereof.
 5. The method ofclaim 2, wherein the silicon-containing precursor includes anaminosilane.
 6. The method of claim 1, wherein a chamber pressure in theplasma processing chamber is equal to or greater than about 7 Torr. 7.The method of claim 1, wherein depositing the first silicon oxide layerby thermal ALD comprises: heating the substrate to an elevatedtemperature; exposing the substrate to a silicon-containing precursor toadsorb onto a surface of the substrate; and flowing hydrogen (H₂) andoxygen (O₂) towards the substrate in the plasma processing chamber whilethe substrate is heated at the elevated temperature, wherein thehydrogen and oxygen react within the plasma processing chamber, whereinthe first silicon oxide layer is formed on the substrate.
 8. The methodof claim 1, wherein depositing the second silicon oxide layer by PEALDcomprises: exposing the substrate to a second silicon-containingprecursor to adsorb onto a surface of the substrate; and exposing thesubstrate to plasma generated from a second oxygen-containing reactant,wherein the plasma drives a reaction between reactive species of thesecond oxygen-containing reactant and the second silicon-containingprecursor to form the second silicon oxide layer.
 9. The method of claim8, further comprising: exposing the substrate to plasma generated from anitrogen-containing reactant, wherein the plasma drives a reactionbetween reactive species of the nitrogen-containing reactant and atleast the second silicon oxide layer so that at least the second siliconoxide layer is converted to a silicon oxynitride layer.
 10. The methodof claim 1, further comprising: depositing a silicon nitride layer onthe first and second silicon oxide layer by thermal ALD or PEALD in theplasma processing chamber, wherein the first silicon oxide layer, thesecond silicon oxide layer, and the silicon nitride layer collectivelyform a silicon oxynitride film.
 11. A method of depositing silicon oxidefilm, the method comprising: heating a substrate to an elevatedtemperature; exposing the substrate to a silicon-containing precursor toadsorb onto a surface of the substrate in a plasma processing chamber;and flowing hydrogen (H₂) and an oxygen-containing reactant towards thesubstrate in the plasma processing chamber, wherein the hydrogen and theoxygen-containing reactant react within the plasma processing chamber,wherein a layer of a silicon oxide film is formed on the substrate. 12.The method of claim 11, wherein the hydrogen and the oxygen-containingreactant react in situ with one another within the plasma processingchamber in an exothermic reaction and drive formation of the layer ofthe silicon oxide film.
 13. The method of claim 11, wherein the elevatedtemperature is between about 500° C. and about 650° C.
 14. The method ofclaim 11, wherein a chamber pressure of the plasma processing chamber isequal to or greater than about 7 Torr.
 15. The method of claim 11,wherein the oxygen-containing reactant includes oxygen (O₂) or ozone(O₃).
 16. The method of claim 11, further comprising: applying plasmapower to the plasma processing chamber to ignite plasma generated fromthe hydrogen and oxygen-containing reactant in the plasma processingchamber.
 17. The method of claim 16, wherein the plasma power applied tothe plasma processing chamber is between about 10 W and about 200 W. 18.The method of claim 11, wherein flowing the hydrogen and theoxygen-containing reactant comprises: flowing the oxygen-containingreactant continuously into the plasma processing chamber; and pulsingthe hydrogen at regular intervals into the plasma processing chamber.19. The method of claim 11, wherein (i) exposing the substrate to thesilicon-containing precursor and (ii) flowing the hydrogen andoxygen-containing reactant are performed cyclically in a thermal atomiclayer deposition (thermal ALD) process.
 20. The method of claim 11,further comprising: purging the plasma processing chamber after exposingthe substrate to the silicon-containing precursor and before flowing thehydrogen and oxygen-containing reactant; and purging the plasmaprocessing chamber after flowing the hydrogen and oxygen-containingreactant.
 21. The method of claim 11, wherein (i) exposing the substrateto the silicon-containing precursor and (ii) flowing the hydrogen andoxygen-containing reactant are performed continuously in a thermalchemical vapor deposition (thermal CVD) process.
 22. The method of claim11, further comprising: depositing one or more additional layers thesilicon oxide film on the substrate via PEALD in the plasma processingchamber.
 23. The method of claim 11, further comprising: depositing oneor more layers of a silicon nitride film on the layer of the siliconoxide film by thermal ALD or PEALD in the plasma processing chamber toform a silicon oxynitride film.
 24. The method of claim 11, furthercomprising: exposing the substrate to plasma of a nitrogen-containingreactant to convert the layer of the silicon oxide film to a siliconoxynitride film.
 25. The method of claim 11, wherein flowing hydrogenand the oxygen-containing reactant comprises: generating oxygen radicalsfrom the oxygen-containing reactant in a remote plasma source;introducing the oxygen radicals into the plasma processing chamber; andflowing the hydrogen into the plasma processing chamber.
 26. A plasmaapparatus for depositing a silicon oxide film, the plasma apparatuscomprising: a plasma processing chamber; a substrate support in theplasma processing chamber for supporting a substrate, wherein thesubstrate support is configured to be heated to an elevated temperature;a showerhead fluidly coupled to the plasma processing chamber fordelivery of precursors and reactants into the plasma processing chamber;an RF power supply configured to power plasma in the plasma processingchamber; and a controller configured with instructions for performingthe following operations: heat the substrate to an elevated temperature;expose the substrate to a silicon-containing precursor to adsorb onto asurface of the substrate in the plasma processing chamber; and flowhydrogen (H₂) and an oxygen-containing reactant towards the substrate inthe plasma processing chamber, wherein the hydrogen andoxygen-containing reactant react within the plasma processing chamber,wherein a layer of a silicon oxide film is formed on the substrate. 27.The plasma apparatus of claim 26, wherein the controller is furtherconfigured with instructions for performing the following operation:apply plasma power to the plasma processing chamber to ignite plasmagenerated from the hydrogen and oxygen-containing reactant in the plasmaprocessing chamber.
 28. The plasma apparatus of claim 26, wherein thecontroller is further configured with instructions for performing thefollowing operations: deposit one or more additional layers of thesilicon oxide film on the substrate via PEALD in the plasma processingchamber.
 29. The plasma apparatus of claim 26, wherein the controllerconfigured with instructions to flow hydrogen and the oxygen-containingreactant is configured with instructions to perform the followingoperations: flow the oxygen-containing reactant continuously into theplasma processing chamber; and pulse hydrogen at regular intervals intothe plasma processing chamber.